The present application relates to a semiconductor structure and a method of forming the same. More particularly, the present application relates to a semiconductor structure including at least one optoelectronic device containing a back contact. The present application also provides a method of forming such a structure.
As microelectronic systems continue to scale down, the resultant electrical density would have to accommodate increased power dissipation, signal delay and cross-talk, while running at extremely high clock speeds. Current trends indicate that in less than a decade the power consumed by interconnects might become the limiting factor in determining the switching speeds in integrated circuits. To overcome these problems, the integration of optical interconnects and systems alongside conventional silicon based microelectronic circuits would be a major step forward. Light base intra- and inter-chip communication would diminish latency considerably and reduce power consumption by eliminating capacitive interconnect loss. Improved optoelectronic integration can also help increase the speed of transceiver circuits used in optical communication systems, thereby increasing the overall band width.
Optoelectronic devices such as III-V optoelectronic devices, integrated in silicon typically use top contacts or side contacts due to the ease of processing only the top surface of the silicon substrate. Despite the ease of formation, top contacts to optoelectronic devices do not offer the same advantages that back contacts to optoelectronic devices do. For example, back contacts to optoelectronic devices can provide uniform current injection, better heat sinking, low series resistance and/or a bottom mirror for light reflection.
In view of the above, there is a need to provide optoelectronic devices integrated on a same chip with conventional CMOS devices in which a back contact is formed to each optoelectronic device.